When I teach adults beginners, I always start slow and build my way up through several stages. First, I just get them to mark a piece of paper in response to my questions, just to see how much they really understand. Second, I get them to repeat answers out loud as a whole class. This gets them used to speaking out, even the very shy ones. Then I ask individual students to repeat out loud, starting with the better students, but giving all students the chance to speak. Then I get them to answer simple questions with only "yes" or "no". Once they get used to responding with one word, I ask them to respond with two words, then three or more. This progression has always worked well for me.

As for specific activities, with beginners I use dictations and basic Q and A techniques mostly. As they progress, they can work on debate or giving short presentations, but that takes time.

Adults are slow-thinking and you can't help it. They rely too much on their consciousness. They don't even doubt that establishing assotiations is the slowest way of retrieving information, the very way we never use in speech. You can't persuade them they are wrong - too much psychology is involved. But you can make them start repeating before they understand a message. The most important thing to remember is that form always prevails. If they don't start thinking they will reproduce the form offered without critical mistakes. What is wrong will come up when they start thinking.